The conventional card edge connector is provided on the upper surface of a circuit board and allows the insertion of an electric card, thereby electrically connecting the circuit board and the electric card. Taiwan Patent Publication No. 392938 (Application No. 84205546) published on Jun. 1, 2000 discloses a linear module connector comprising an upper layer connector and a lower layer connector. Both connectors are stacked in a vertical direction. The upper layer connector and the lower layer connector each comprise an insulating body having a central slot (insertion slot). The insulating body is provided with a plurality of terminals for electrically connecting the electric card and the circuit board.
As shown in FIG. 1, the insulating body 91 of the conventional card edge connector 9 is provided with an insertion slot 911 for allowing the insertion of the electric card 8. Since the insulating body 91 is made of plastic material, and the insertion slot 911 is formed into an elongated stripe, it is prone to deformation. As a result, it is not easy to insert the electric card 8. Therefore, the insertion slot 911 is usually made wider to facilitate the insertion of the electric card 8, thereby preventing the deformation of the insertion slot 911 which in turn may block the insertion of the electric card 8. However, in such situation, the electric card may not be stably fixed into the insertion slot and the stability thereof is poor. As a result, it is difficult to ensure the electrical connection between the electric card and the card edge connector. Therefore, the electrical properties between the electric card and the card edge connector are poor. In view of this, the inventor proposes the present invention to overcome the above problems based on his expert experience and deliberate research.